THAT’S A WRAP! Justin Tuck, who rode a stationary bike with his left shoulder wrapped at practice yesterday, is listed as questionable for the Giants’ key matchup with the Ravens tomorrow. Photo: Bill Kostroun

In keeping with the most disappointing season of his career, Justin Tuck now appears likely to miss the Giants’ most important game of the season.

Big Blue is officially listing their defensive captain as questionable with a shoulder injury for tomorrow’s crucial visit to Baltimore, but Tuck didn’t practice all week and sported the hangdog look of a player headed for a Sunday in street clothes both during and after yesterday’s workout.

Coach Tom Coughlin didn’t exactly give off an air of confidence, either, that the 8-6 Giants would have Tuck in the lineup when they take on the 9-5 Ravens at M&T Bank Stadium with their entire season potentially on the line.

“We’re going to have to wait and see on that one,” Coughlin said when asked about Tuck’s availability.

If Tuck’s shoulder — which Coughlin said was injured in last week’s 34-0 loss to the Falcons — doesn’t show significant improvement today, that likely would mean more playing time for Adrian Tracy as the Giants try to rediscover a once-fearsome pass rush that has been invisible lately.

Tracy, a sixth-round pick two years ago who can swing between linebacker and end, has appeared in all 14 games this season and recorded his first career sack in the Oct. 14 win over the 49ers.

All but three of Tracy’s appearances this year have been on special teams, though, which would mean a big step up if Tuck can’t go. But if playing a significant role or perhaps even starting in such a pivotal game is daunting to the William & Mary product, Tracy didn’t show it yesterday.

“I’ll be ready, and if I’m called upon, I’ll fill my role,” he said after practice. “I would be ecstatic to get out there. This is what you want to do — you want to play, you want to get out on the field. When I got that opportunity in San Francisco, I was on Cloud Nine. If it presents itself this week, I’ll have the same feeling.”

Then again, it’s not as if Tuck’s play this season would mean leaving big shoes for Tracy to fill. Tuck, a two-time Pro Bowl pick, has just three sacks this season (the fewest since his rookie year in 2005) and has been all but invisible since recording two of those sacks in a Week 10 loss to the Steelers.

Tuck didn’t speak to the media after practice yesterday, but even he admitted the day before that his play hasn’t been up to par this year and much of last season. A neck injury limited Tuck to just 12 games in 2011, ending a streak of four consecutive seasons in which he had played in every game.

When a reporter told Tuck on Thursday that Osi Umenyiora had said the Giants wouldn’t hesitate to replace their prominent pass rushers after the season if they didn’t start producing sacks again, Tuck didn’t disagree.

“That sounds about right,” he said.

Tuck’s absence yesterday was a surprise because Coughlin had said Thursday he expected the veteran defender to be healthy enough to participate.

Tuck didn’t suffer a setback, according to Coughlin, but wasn’t allowed to practice on the recommendation of team doctors. That decision didn’t go over well with Tuck, who watched practice from the sidelines with his shoulder heavily wrapped and a forlorn look as he rode a stationary bike.

That pride and determination have resulted in “miracle” recoveries before by Tuck, which might be why the Giants still aren’t ruling him out completely or even listing him as doubtful on the official injury report.

And even if Tuck can’t play, the Giants still might go against their protocol and have him on the sidelines in Baltimore simply for his veteran leadership.

“I feel a lot of responsibility for this team,” Tuck said this week. “I want to be out there, because this is a huge game. We’ll see what happens.”